Proximity operators express a relationship between search terms as they are found in a document.  These are powerful connectors that allow you to greatly refine a search.
 

• /p finds documents which contain the terms within the same paragraph.

“regulatory taking” /p “endangered species”  1 -- case
 

• /s finds documents which contain the terms within the same sentence
 
“regulatory taking” /s “clean air act”  1 -- case
 

• /n (where “n” is a number) finds documents which contain the terms within the given number of words (either preceding or following) from each other.

paul /3 callister
 
Note: It is almost always a good idea to search for a person using the method above.  Scholars often use a middle name or initial of which the searcher might not be aware. 

• To require a certain order for the terms use pre/n.

peter pre/3 hook
 

• (LEXIS ONLY) To exclude a certain proximity use not /n.
 
(peter pre/3 hook) not/3 (pan or captain)